Depth sensing camera systems can be used for a variety of purposes, all of which depend on the accuracy of the data received from the object whose depth is to be detected. Many such systems use a projector to illuminate a target with a random or pre-defined pattern, and which detect the distance to the target using data from the reflection. Data from the pattern is used by a depth sensor to determine depth information.
One type of system uses a laser or laser diode as a projector. An issue with at least one current design is the stability of the wavelength of the laser. Detection systems are designed to read reflections based on the output wavelength of the laser. While lasers operating at constant current and temperatures have negligible wavelength fluctuations, optics used with such systems may destabilize the wavelength due to optical feedback from the optics in the system. An additional issue with use of laser light as an illumination source is that when the coherent light from the laser is re-imaged to the detector, there is noise in the form of a speckle pattern. This creates a fundamental limit as to how accurately one can determine the position of the feature in the image.